TFA (0.030 mL) was added to a solution of (9-(4-(2-hydroxyethyl)benzyl)-1-oxa-4,9-diazaspiro[5.5]undecan-4-yl)(2-methylthiazol-4-yl)methanone (example 16, step b) (0.16 g) in DCM (5 mL) at 0° C. and the resulting mixture stirred for 5 min. Dess-Martin periodinane (0.245 g) was added and the mixture allowed to warm to room temperature and stirred for 45 min. A mixture of saturated sodium thiosulphate solution (5 mL), saturated sodium bicarbonate solution (5 mL) and ethyl acetate (20 mL) was then added and the resulting mixture stirred for 10 min. The aqueous phase was separated and extracted with ethyl acetate (20 mL). The combined organic solutions were washed with brine. AcOH (0.1 mL) was then added and the mixture dried over sodium sulphate, filtered and evaporated in vacuo to give the subtitled compound as a clear oil which was used immediately. Yield 0.16 g.
